1. Field of the Invention
This invention relates to vacuum cleaners and in particular to means for cooling a wheeled drive motor of a self-propelled vacuum cleaner.
2. Description of the Prior Art
In one form of vacuum cleaner construction, as shown in U.S. Pat. No. 2,980,939 of Charles H. Sparklin et al., owned by the assignee hereof, a vacuum cleaner nozzle structure is provided with a motor driving a rotatable brush by means of a belt connection therebetween. The motor is cooled by an air flow which is drawn into the motor by a conventional motor cooling fan provided in the motor. Cooperating seal flanges and wall means divide the interior of the nozzle into an upper passage for conducting relatively clean air to the motor and a lower air passage for conducting the dirt laden air to a suction means. As shown in FIG. 9 of the Sparklin et al. patent, air may be conducted through an opening 10a in the nozzle into the motor openings 18a, through the motor, outwardly through the motor openings 18b, and outwardly from the upper air passage. As shown, the motor is fixedly mounted to the nozzle, permitting the simple air flow arrangement.
In U.S. Pat. No. 3,675,268 of Erwin E. Nordeen, also owned by the assignee hereof, a vacuum cleaner construction is illustrated having a fan motor which is cooled by clean air delivered from the dirt collector into the motor housing and after passing through the motor housing, through suitable discharge openings to the ambient atmosphere.
In copending application Ser. No. 323,779, filed Jan. 15, 1973, now issued as U.S. Pat. No. 3,854,164 of Joseph F. Schmitz, and owned by the assignee hereof, a self-propelled upright vacuum cleaner construction is disclosed wherein cooling air is provided to the motor for driving the wheels thereof. A number of different embodiments are disclosed illustrating different methods of delivering the cooling air to the wheel drive motor.
Of the references cited by the examiner in said copending application, the most pertinent to the present invention would appear to be those of Melvin H. Ripple et al. U.S. Pat. No. 3,618,687, and Donald G. Smellie U.S. Pat. No. 2,300,266. These patents are considered pertinent in being directed to vacuum cleaner constructions utilizing two motors, including a motor for driving the suction fan means.